An element is an object that you can put inside a pipeline, wrapping some operation on the media inside.
元素是可以放入到管道中的对象，其中包装了对媒体进行的某种操作。
2
China-Russia oil pipeline has been formally put into operation and the bilateral cooperation in the energy fields of coal, natural gas and electricity moves forward steadily.
中俄原油管道正式投产运营，煤炭、天然气、电力等能源合作进展顺利。
3
Listing 1 illustrates an XProc pipeline with a single step that applies an XSLT operation to an XML document.